<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var arr = [1, 2, 3, 4, 5];
        console.log(arr.toString());// 1,2,3,4,5
        arr.push(6, 7);
        console.log(arr.toString());// 1,2,3,4,5,6,7
        arr.unshift(-1, 0); 
        console.log(arr.toString()); // -1,0,1,2,3,4,5,6,7

        arr.pop();
        console.log(arr.toString()); // -1,0,1,2,3,4,5,6
        arr.shift();
        console.log(arr.toString());// 0,1,2,3,4,5,6
    </script>
</body>
</html>